Definition: In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.
Input: ['z', 'p', '1103', '3689', '4205', '2505', '1201', 'l', '5837']

l, p, z